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Improvements at Mouths of the Missis¬ 
sippi River. 



REMARKS BY PROF. FOltSHEY 

Before the Senate Committee on Transportation, and also the 
House Committee on Railroads and Canals , on ths question of 
Improvement of Navigation at the Mouths of the Mississippi 
River. 


't.U 


In substance the Professor said: That he was a civil engi- /r 
neer by profession, and had^ devoted a large share of his 
professional labors to the investigations of the physics and 
phenomena of the Mississippi river; he believed much more 
of time and personal labor than any other one man, living 
or dead. 

That now he represented the New Orleans Chamber of 
Commerce, of which he is an active member, in their earnest 
effort to get such legislation, as to insure deep and perma¬ 
nent navigation, from that great river out to the sea, for the 
already stupendous and actively growing commerce of the 
Mississippi valley. 

That he had been observant of, and familiar with all the 
surveys and efforts to improve the natural channels, since 
that of Captain Talcott in 1838; that he had made several 
of the investigations in person ; two of the most thorough 
that have ever been made; the one by the State of Louisiana 
in 1849-50, and the other in 1851-2 under the United States, 
in the Delta Survey by Captain Humphreys, now the honored 
Chief of Engineers. As engineer employe he had conducted 
the hydrometric labors of that survey, and made two elabo¬ 
rate examinations, one in high and the other in low water, 


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to determine the depths, currents, and materials transported 
over, as well as lodged upon the bars, at the several mouths 
of the river. 

In all these labors, extended over more than 34 years, he 
had been taught modesty and humility, in the presence of 
the gigantic torrent. While, in a hundred ways, he had 
been able to guide the surface waters along the channels, by 
pigmy levees—whenever the deep abrasions, beyond the reach 
of the human eye or hand, turned towards his works, he had 
learned to retire before the dread forces, and place the feeble 
works beyond the reach of his devourings, even to the con¬ 
struction of the third and fourth parallel, miles back from 
the original defence. 

He came now before men of judgment to confess his dis¬ 
asters, his failures, and to acknowledge his supreme’ impo¬ 
tence to make channels, or preserve them when made by the 
Missississippi river. He had no theory to offer, but most in¬ 
structive experiences to relate. These experiences have the 
merit of candor, however disastrous ; and they claim to be 
swayed by no hope of personal gain, other than those that 
await the candid student of nature and of truth. 

In reply to the question— 

Do you believe that one or more of the river’s mouths can 
be improved in channel, so as to give deep and permanent 
navigation for commerce? the Professor said “I do not; I 
believe it not only impracticable, but impossible; and for 
these reasons: 


BARS 

Are formed at the mouths of all streams, whether tidal or 
contributary streams. At the point of equilibrium between 
the waters inside and outside, there will always be a bar. 
The constitution of these bars will be as various as their 
numbers, and little or nothing can be inferred as to one from 
the phenomena of another. Each has to be studied by 
itself—has its own physics. 


3 


Sediment-bearing rivers contribute the material (mainly) 
that form their own bars. The Mississippi bears sand and 
aluminous clay or mud of very tenacious character. These, 
variously commingled or separated, form its alluvion. In 
some localities over the great length of the alluvion, sand 
prevails almost pure ; at others, the blue clay prevails, so te¬ 
nacious as to resist the spade; and its taste is without grit. 

These materials do not generally travel together. Sand 
is rolled forward on the bottom; clay is dissolved or finely 
divided and carried in suspension by the river. 

During low-water season, the river scarely moves its bur¬ 
den of sand; the channel almost chokes with it, while the clay 
is, in great measure, at least, held in suspension in the mov¬ 
ing water. In high-water season, the sand is easily pushed 
forward up the incline of the bar, and over into the Gulf. 
Very little of it lodges, but it is carried to sea, and around 
into the residuary bays. 

Whether in high or low-water season, the clay, in sus¬ 
pension, is held till the river waters mingle with the salt 
water. Then it is precipitated , and falls to the bottom, just as 
river water is settled in our coolers, by treating with a little 
alum or soda. This always occurs upon and on the outer 
slope of the bar, and whenever a particle of it touches its 
neighbor on the bar it adheres with tenacity. The water 
glides over it as if it were soap. This is its feeling to the 
touch. No moderate current can detach it. It forms 

A BAR OP MUD OR PLASTIC CLAY, 

Only alternated by thin and occasional laminae of sand. 
This is the character of all the bars. They are soft and 
tenacious, so that a pole thrust in and withdrawn is always 
smeared with mud. 

This mud has a dough-like plasticity, such that the chan¬ 
nels in it, if cut deeper by harrowing or dredging, fill by 
lateral pressure. The dough resumes its level. The channels 
have a normal depth of 12 to 15 feet. You drive a vessel 


4 


through, with a draft two feet deeper than soundings, and it 
leaves no trough at two hours after. The dredging of our 
powerful boats, the Essayous and the McAllister, give 19 
feet navigation in 17 feet soundings ; where they attacked a 
bar of 14 feet channel, and these dredgings are lost in a 
week’s cessation of work, no matter when suspended. 
Dredging or stirring must be 'perpetual, and can only reach 
about 19 feet, whatever the power applied. The bar at this 
depth is more than three miles long, and requires for a 300' 
channel, 150,000 cubic yards of work per foot of depth, and 
a total of 579,000 cubic yards moved, say weekly, to keep 
20' depth. At the end of one week thence, a like 579,000 
yards pressing in from the sides, would replace what had 
been put in motion. This would demand five such steamers 
as have been at work; and even then storms and accidents 
would peril and destroy all our work, and blockade our 
commerce. So much for stirring and dredging.* 

This material forms the bars, and largely the shores about 
the passes. 

THE PRECIPITATION OF THE SEDIMENT 

Occurs at and beyond the point of equilibrium, between 
river current and sea-level resistance. 

The river water, being fresh, is lightest, and mounts the 
barrier of the Gulf by spreading out gradually over the sur¬ 
face : so that we find the turbid water at twenty or thirty 
miles out to leeward of the mouth ; and yet so thin as to part 
for the keel of vessels, and show the green salt water beneath. 
The under surface of the river water mingles with the salt, 
and precipitates its alluvion. 

Each mouth pushes away at its own bar and drives it to 
sea, for it 

*The Professor said that the appropriation for dredging was ex¬ 
hausted and the work suspended on the 1st of March. On the 10th, 
the 17' channel was 14 / .5, and on the 14th, twenty vessels were 
waiting to be lightered in, and fourteen out, at the bars. The effect 
of the powerful dredges was entirely lost. 



5 


BUILDS A JETTY 

along the sides, concentrates its current upon the bar, and 
drives it further out to sea, where the new equilibrium oc¬ 
curs ; and there it builds its new bar, and throws down its 
alluminous burden in and about the channel; and this bar, 
with the normal depth, under fifteen feet, it stubbornly holds, 
and recreates. 


THROUGH THE CENTURIES ! 

The river has thus formed and maintained 87 miles of jetties, 
below the head of the passes, flanked by narrow strips of 
land, and has tried to make a channel in 17 different passes, 
that still there survive only two of these which, now projecting 
out and discharging their waters 25 miles apart, have any use¬ 
ful depth for navigation. The old tyrant has abandoned the 
conflict in 15 of the 17 passes, and does not pretend to more 
than 14 feet of reliable water, on either of the present 
bars. For 150 years he has been able to do no better. All 
human agencies have been impotent to do more than stir 
the mud, and give navigation 19 feet. 

ABOVE THE PASSES, 

Nature made a single jetty of 60 or 70 miles, and brought 
the entire force of the river, of 200,000 square feet area, 
moving at 4 feet per second, or nearly a million cubic feet 
per second, and hurled it upon the bars; and still nature was 

CONFRONTED BST A MUD BOTTOM 
and shallow water. 

Nature, then, can make only 14 feet channel, by use of 
jetties, however long and high, even with this momentum of 
more than 100,000 horse-power, or 150,000 tons, hurled at 
every second against the bars. 

Such, too, is the softness of the material, that 


6 


NO WORK CAN BE CONSTRUCTED UPON IT. 

The weight of a log lying upon the shore usually sinks it into 
the mud. The pillars and abutments of the buildings about 
the mouth continually sink, and others have to be inserted 
upon them. 

In 1849, on the Ricker survey, we sought for the old 
French fort on the Balize bayou, remembered by the older 
pilots; but it had sunk, with its huge magazine of brick, 
below the surface, and could not be found. Such is the soft¬ 
ness of the shores, the bars, and the channels. 

THE MUD LUMPS, 

which rise at times 10 feet above the surface of the water, 
gradually subside to the level of the Gulf, and often below 
it. As soon as the power that lifts these strange protrusions 
is relieved, the head retires to the general level of the land; 
so that the surrounding marshes, now permanent portions of 
the shore, have none of these mud lumps, nor any protru¬ 
sions above the general level.* Such is the lack of solidity, 
that all lands soon attain a level but little above the actual 
Gulf. It requires years, probably many centuries, to attain 
compactness adequate to maintain banks for bayous or 
canals. 

Therefore, no artificial jetties, rising above the sea-level, 
would stand ; and if not above the sea-level, the water would 
extravasate, and its abrasive force be lost, as at present, and 
the jetties would not affect the bar. 

THESE MUD PROTUSIONS 

Have probably an artesian source. The waters of springs 
or streams, with sources away in the uplands, become choked 
at their gulf mouths, by the blanket of soft mud thrown 


* A single mud lump thrust its head up in the prairie, some miles 
up the passes. It is the only one since my observations or any 
records. 



7 


over them, and in their struggles to escape, they bring to 
bear a force proportioned to the height of their sources. 
And after lifting the rounded head of these vast masses, 
uutil they are ruptured by the flexure of the mud strata, the 
water escapes, and the island subsides. Yet they often 
stand for years; and then gradually sinking round their 
margins, the head is washed off by the waves or sinks to 
sea-level. These mud lumps are sometimes protruded through 
the shoal water above bars along the channel sides, outside 
the land, but chiefly where deposits are greatest, and right 
about the bars. 

A FEW HOURS 

At times, brings them to the very surface, right across the 
channel upon the bar. I was spending the night upon the 
pilot boat, for current observations, in 1852, when we were 
suddenly compelled to change the location of our boat to 
escape being lifted out of water, by a rising mud lump. 

Such an upheaval would destroy any works or channels 
we might make. I computed the lifting power of one of 
these, 600 feet wide and 1000 feet long; it had a minimum 
force of 

61,000 TONS. 

I appeal to Captain Eads, General Barnard, Brunei, Ste- 
verson, or any other man, to tell me what would become of 
his artificial jetties, in the presence of a lifting power of 
60,000 tons? They are so common that the people 
about the passes can number them in scores and hundreds. 
The most recent coast survey, 1873, shows 29 of them east 
and 24 west, along Southwest Pass, outside of the land; they 
appear and disappear, in all sizes, from 50 feet to 1000 feet in 
extent. If these were the only obstacles, they are inevitable, 
and render artificial jetties utterly futile and impossible. 

jetties 

Can only increase the currents by damming up and raising 


8 


the water. You can only hasten a current by giving it 
greater fall—a steeper plane ; this, and this only, will in" 
crease the velocity of water. 

But if you dam up the water by jetties, you drive it out by 
the other passes, and lose your current and your channel. 

To serve the purpose of jetties, complete levees would have 
to be built, for forty miles up the river, and cut off the whole 
of the other passes, and drive all the water through a single 
pass—the Southwest, for example. This would treble the 
water, and the deposit, and the rate of progress of the bar, 
and give it a mile in four or five years, instead of fifteen 
years, and would cost indefinite millions, if at all possible. 

For these and like reasons, I pronounce the scheme of 
jettying the river, to accomplish deep and permanent navi¬ 
gation to be visionary, impracticable, impossible. 

To the question— 

What do you think of the practicability of the proposed 
Fort St. Phillip canal; what would be its extent, and the 
character of the grounds on the line? the Professor replied, 
“ I believe it entirely practicable ; a great, though not a very 
formidable work, with probably expensive and dilatory con¬ 
tingencies ; 


AND EOR THESE REASONS. 

1. It would have a length of seven miles and a fraction, and 
the line would traverse sea-marsh and shallow ponds of 
water to the Gulf shore, and would then extend a half mile, 
more or less into the Gulf to 4 5 fathoms water. On the 
shortest line, as surveyed by Major Howell, the distance to 
this depth is a mile, or a little more. A line recently sur¬ 
veyed by me would leave the river two and a half miles 
further up, and, with a reverse curve, pursue a land route 
nearly all the way to the Sable island, and reach deep water 
in a little more than half a mile, with a total length of about 
7f miles. 


9 


2. Every mile further removed from the present mouths of 
the river, we find land that has had more time to consolidate, 
and by continual pressure, to extravasate its water, and bring 
the particles of this plastic clay more and more in apposition; 
that chemical affinities thus have had their effect of consoli¬ 
dation. The borings made by Major Howell, six in all, (a 
very inadequate number for detailed location,) exhibit suffi¬ 
cient compactness to support banks. With slopes such as 
those prescribed, they would stand without masonry or much 
reveting. 

3. And, while I believe that several modifications might be 
advantageously made, so as to be added to the plan, after con¬ 
struction or before, I do believe that the estimate is large 
and liberal; and that it will invite many bidders to under¬ 
take it, at figures considerably under the estimate of the en¬ 
gineers. 

The Professor concluded : 

“I cannot express the energy with which I am impressed, 
that the canal furnishes the only rational solution of the 
demand for deep navigation, from the Mississippi river out 
to deep water in the Gulf of Mexico.” 

After the conclusion of the Professor’s remarks, a number 
of questions elicited the following: 

“ What length of time would be a fair test of the perma¬ 
nence of jetties, or the channels, say 20 feet or 22 feet, made 
by them ; six months, twelve, or fifteen months? ” 

Ans. “These periods would prove nothing; six months or 
two years as a test would be trifling with the great subject. 
Ten or twelve years would afford a fair test of the usefulness 
of jetties, but not of their permanence. Fifty years or a 
century, the life of a nation would be adequate. However, 
he did not believe that the jetty could stand one year with¬ 
out showing by its settling, whatever base it might have ? 
that its life is extremely brief, 

2 


10 


The Professor considered the authority of The Danube, as 
bearing on the value of jetties, to be of no weight whatever, 
and for these reasons: 

1. The shores of the Sulina mouth are solid ; so that stone 
buildings stand on them. 

2. An abrading, littoral current was ascertained before 
this experiment. The shore at the Salina mouth was eroded, 
showing a tendency in the sea-water to carry off the deposits. 

3. No current exists at the mouth of the Mississippi. He 
had sought them in vain, under instructions. The superin¬ 
tendent of the Coast Survey, Captain Patterson, many years 
engaged on that station, says “ no littoral currents have been 
found, only such temporary currents, as the wind for the 
time being, creates.” 

He insisted upon the distinction between a “ tidal ” and a 
littoral current. The tidal currents were of influx and 
efflux; and as modified by the winds, acted an efficient part 
in accretion of the shores, by distribution of the river’s con¬ 
tributions in the residuary bays, and upon the bars. He 
recognized these currents, and measured them as reported in 
the “Delta survey.” 

A littoral current (not found,) would be one running par¬ 
allel with the shores, and pertaining to the physics of the 
Gulf. Such a current would be expected to bear away to a 
distance the river’s silt. That none such has ever existed in 
this portion of the Gulf, is absolutely proved by the indefi¬ 
nite projection of the jettied mouths of the river. 

If such current existed, why has it not carried off the de¬ 
posits that continually push these bars to sea? 

4. Before the Danube can be cited as a permanent jetty, 
let us have a century of result, and then as now we say that 
it is no authority for our river. It is too ridiculously small 
to be considered other than as a canal. It carries but T 2 T as 
much water as the Southwest Pass, or say of the Missis- 


11 


sippi river, and runs at double the rate.—The total want of 
analogies deprives it of all authority respecting operations 
on the Mississippi. 

' To the question, “ How long it would take to construct 
the canal?” the Professor replied, “ three to five years.” 

Question. 44 Why can the canal maintain its banks, if the 
bars are so soft ?” The Professor repeated his answer. 4 4 The 
borings of Major Howell, to 60 feet depth proved the greater 
consolidation of the alluvial material; that it appeared suf¬ 
ficiently reliable. The bayous in rear of Fort St. Phillip 
have considerable depth, 15 to 20 feet, and stand well with 
steeper slopes. The canals cut for rice and sugar crop 
drainage, aud oyster canals, all stand well. Every mile up, 
is clear gain in respect to solidity.” 

He here took occasion to say that the want of 

A HARBOR 

About the river’s mouths had always been intensely felt. 
However good the navigation at the passes, they could not 
be entered in very rough weather, and vessels were obliged 
to put to sea. This canal enters a secure harbor, with five 
square miles entirely land-locked, and five times that area 
covered on three of its four sides. This alone furnishes suf¬ 
ficient reason for the construction of the canal. 

To the questiou, as to the sufficiency of the surveys already 
made, and whether a better route might be found, the Pro¬ 
fessor answered : 

44 The surveys are sufficient, as I believe, to enter upon 
the work. Absolute detailed location and plau are not im¬ 
portant. As in the St. Louis bridge, aud other great works 
many contingencies may alter the plan. The engineer 
board should locate under orders of the Secretary of War, 
and modify details of either location or route, according to 
experiences in construction.” 

Upon pretty searching questioning, the Professor stated,that 
he believed that hundreds of borings would have to deter- 


12 


mine the route, which might develope pockets of quicksand, 
that should be flanked, whenever or wherever found; that 
he had entire faith in the practicability, by the theoretical 
line of Major Howell, or by another line he had recently 
surveyed, starting at nearly the same Gulf debouche and 
winding a little further north. An all-land-line might be fol¬ 
lowed which would be J mile longer, and have but J mile of 
jetty, in water of over 5 feet depth. He therefore hoped, that 
the estimates would be greatly reduced, in construction. That 
the ablest of American contractors had estimated upon the 
United States engineer board specifications, and had offered 
to take the contract at those estimates, and guaranty by a 
large bond, to complete the work under the United States 
engineer, within three years. Prudently enough those who 
propose to improve the channels by jetties, offer no security. 

In rejoinder to Captain Eads’ criticisms, Prof. Forshey 
says: 

The further the bar is driven out by jetties, or the ordinary 
process, the longer the plane, with the same fall; and hence 
the less the velocity and abrading power of the current. 

This was an axiom, and he would not repeat it. 

Again: 

The velocity relied upon to cut the bar, has to precede the 
depth upon which he relies for his greater velocity. Now, 
if greater depth upon the bar is to give greater velocity, 
that depth must precede the increase of force. The effects 
are not likely to precede the cause. 

lie and friends object that the canal is inadequate. 

We propose, ultimately, a triple-lock at the river, and 
that shall pass 200 vessels a day—say a lock for 12 feet ves¬ 
sels; one for 18 feet; and one for twenty-five feet. The 
one will answer for the present, and will pass 50 vessels per 
day, or more, with ease. 


13 


Again: 

He dissented from the statement of Captain Eads, as a mat¬ 
ter of river physics, that “the greater the velocity, the greater 
the load of sediment held in suspension and transported.” 

Any particle of earthy matter transported is indifferent to 
velocity. If the threads of moving water are parallel, so as to 
give tranquil lapse of the body, the particle will sink by its 
specific gravity, as well in a ten as a two-mile current. It is 
only transverse or oblique movements from the bottom and 
sides of the channel that can keep the mineral matter from 
subsidence. And the river carries no more at high than low 
velocities, except as it attacks the sides and bottom irregula¬ 
rities, and by oblique currents lifts small quantities that 
have been deposited. By slight change of the statement, 
Captain Eads would do no violence to physics; thus, the 
greater the velocity the more power to move forward the 
mass of matter rolling along the bottom. But this velocity 
has little effect on the slimy or soapy matter constituting the 
bars. The sand drift at the bottom of the channel rolls 
over it, leaving only a few grains that touch the surface 
of mud, and the mass is carried to sea, or round into the 
residuary bays, by the tidal currents. 

Again : 

Captain Eads reads a number of letters from engineers, 
who, like himself, are eminent for their success in building 
great bridges, and for other railroad labor—all giving opin¬ 
ions favorable to his jetty scheme. 

I respectfully deny the authority or weight of such vol¬ 
unteer opinion, in the absence of investigation by these 
engineers. Neither of the writers (I believe) has ever seen 
the mouths of the Mississippi, and I have to suggest that 
they have not much enhanced the just reputation which I 
yield them, by thus hazarding opinion, in the most recondite 
and difficult branch of our profession, without previous sur- 


14 


veys aud investigations. How much value would Captain 
Eads or either of his endorsers attach to my opinion, as to 
bridge-pier foundations on the Upper Mississippi or Missouri 
river, where I have only visited and viewed superficially ? 
They will pardon me if I call upon you, Senators and Con¬ 
gressmen, to discredit, or weigh lightly such engineer cer¬ 
tificates, in the absence of investigation. 

And, Captain Eads must pardon me, if I call attention to 
the advantage he possesses, in the prospect of a ten million 
contract, to stimulate both effort and opinion. No man has 
ever had so stupendous a contract. Before such a sum of 
money, Senators, statesmen, judges, philosophers, and even 
great engineers, may well pause and analyze their own 
hearts, and answer to themselves, whether its attractive 
seductions may not have colored their opinions. And while 
yielding to my urbane and accomplished professional brother 
the meed due to an honorable and sincere man, 1 would 
propose to join him in a passage from the prayer of our 
Great Master— 


“ Lead us not into temptation.” 




































































































































































































































































































































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